Pulmonary injury following smoke inhalation represents a common clinical, radiological and pathological entity. How inhalation of smoke leads to bronchoconstriction, atelectasis and pulmonary infection remains unanswered. Alteration of surfactant, a major component of the alveolar lining material, and airway cellular content and function may be important in the pathogenesis of smoke-induced lung injury. The purpose of this study is to investigate the effects of smoke inhalation on the lungs. Utilizing an exposure chamber designed in this laboratory, rabbits will be exposed to the products of pyrolysis and combustion. Rabbit lungs will be examined histologically and sampled by bronchoalveolar lavage for (1) surfactant phospholipid, (2) protein and cellular contents, and (3) alveolar macrophage function. In addition, the therapeutic efficacy of corticosteroids, antibiotics and aminophylline in smoke-induced pulmonary injury will be evaluated.